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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Trane XR90 furnace iginiton issue. heat on thermostat demand

Customer Question

Trane XR90 furnace iginiton issue. heat on thermostat demand blower and purge fan spin up. gas flows. no igniter SIlcone Nitride reading 15.1 ohms. Condensate tubes are clean. any other checks?
Submitted: 1 year ago.
Category: HVAC
Expert:  airheatman replied 1 year ago.

Are you getting an error code on control board?

Customer: replied 1 year ago.
flashing for heat demand. Since initial question additional checks. Limit switch is shows continuity. purge fan is not running. removed and checked it to spin. spins freely.
Expert:  airheatman replied 1 year ago.

Does the flash not change when it fails to work? If it does not light we should get a different code.

Customer: replied 1 year ago.
no same error flashing continuous - not pause.
Customer: replied 1 year ago.
check it 3 times. power cycling
Expert:  airheatman replied 1 year ago.

Sounds like a defective board to me. As you can see by chart I sent, board should be giving us an error code if furnace does not work properly.

Customer: replied 1 year ago.
that's it ?
Expert:  airheatman replied 1 year ago.

I hate to condemn the board without being there, but the board is there to help us troubleshoot.If the board is not giving us an error code when we know there is an error, board is failing to do its job.

Customer: replied 1 year ago.
this is not worth the $28. I request a refund.
I would have expected more diagnostics.
Expert:  airheatman replied 1 year ago.

You should see a drop down list to request a refund.

Expert:  airheatman replied 1 year ago.

I have opened to other experts. First you indicated that purge fan was running.That is good.But you also stated gas flows but igniter does not glow.That is not good. Then you stated after checking again that purge fan does not spin.That is not good.If purge fan does not spin you should automatically get an open pressure switch code and board should definitely not allow gas to flow.You state that although purge fan motor does not work and igniter does not work, we get an "all clear" normal code. All point to a failing board.

If there is a specific thing you would like to test, post that here and one of us will help you test that particular part.